His village was attacked by the Fire Nation before Team Avatar arrived there. His father and the other earthbenders managed to defeat the invaders at first, but they were powerless when the Fire Nation came back with their war machines. As a term of surrender, the nonbenders of the village were allowed to live in peace, if the earthbenders were imprisoned and earthbending forbidden. Their earthbending-related tools were also confiscated.
Fire Nation soldiers were apparently not aware of his earthbending ability. When he threw a pebble at the lead solider, he was pursued until he stumbled upon Team Avatar. They were all captured and escorted to a prison camp to be reunited with his father.
Upon inquiry, his father explained the situation to Aang. Team Avatar were in trouble when they tried to instigate a prison uprising, so he threw a pebble at the lead soldier. His father earth-blocked a retaliatory fire attack, even though it was not acceptable for any prisoner to do so. His father held him close, waiting to be finished off by a combined attack from two firebenders when they were protected by a large earth-barrier, raised by six earthbenders bending in unison.